Is it possible to assign a parent to a control point of a curve using animall?
I am not sure how this works with the AnimaAll addon but the way I would approach this is to:


Select the control point of the curve in edit mode that you would like to attach to the head.
Press Ctrl+H to 'Hook' the control point, choose 'Hook to New Object'.
A new empty will have appeared that the control point will be parented to via the hook modifier that was just added. Parent this empty to the head in object mode by Shift selecting the empty and then the head and press Ctrl+P and choose 'Object' as the parenting type.


The control point is parented (via the hook modifier) to the empty and the empty is parented to the head.

The hook modifier can also be added by manually choosing to add a new hook modifier to the curve like you would add any other modifier.